Laminate battery and method of manufacturing the same

A method of manufacturing a laminate battery including an electrode body, an exterior body having a pair of exterior films that are opposed to each other with the electrode body sandwiched between the exterior films, an electrode terminal having a plate shape, and having a first end portion connected to the electrode body and a second end portion exposed to an outside of the exterior body, and a thermally weldable film that covers a surface of the electrode terminal disposed between the exterior films, the method comprising:

• forming a laminated body in which the electrode body to which the electrode terminal is connected is disposed between the exterior films, and the second end portion of the electrode terminal is exposed to an outside of the exterior films, while the surface of the electrode terminal disposed between the exterior films is covered with the thermally weldable film;
• placing an end portion of the laminated body in which the electrode terminal is interposed between the exterior films, between a pair of pressure plates;
• heating the pressure plates to a predetermined temperature;
• and
• forming a welded portion by sandwiching the end portion of the laminated body between the heated pressure plates, to pressurize and heat the end portion, the welded portion including a film welded portion in which the exterior films are welded to each other, and a terminal welded portion in which the exterior films are welded to the electrode terminal,
• wherein the thermally weldable film has a protruding portion that protrudes from a side face of the electrode terminal in a depth direction, and
• wherein a length of the protruding portion is equal to or larger than 50% of a thickness of the terminal welded portion, and is smaller than 100% of a length of the film welded portion.